[llvm-branch-commits] [compiler-rt] [TySan] Fixed false positive when accessing offset member variables (PR #95387)

[Jeremy Morse via llvm-branch-commits]

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@@ -0,0 +1,31 @@
+// RUN: %clang_tysan -O0 %s -o %t && %run %t >%t.out 2>&1
+// RUN: FileCheck %s < %t.out
+
+#include <stdio.h>
+
+struct X {
+  int a, b, c;
+} x;
+
+static struct X xArray[2];
+
+int main() {
+  x.a = 1;
+  x.b = 2;
+  x.c = 3;
+
+  printf("%d %d %d\n", x.a, x.b, x.c);
+  // CHECK-NOT: ERROR: TypeSanitizer: type-aliasing-violation
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jmorse wrote:

I'm not familiar with the output of TySan, but this CHECK-NOT paired with the CHECK on line 28 is going to test that "there's no error until there's an error", which makes this specific CHECK-NOT redundant. If you're looking to ensure there's only one instance of that error-output then you need to put another CHECK-NOT under the CHECK lines below, or add `--implicit-check-not` to FileCheck. Also consider just not having this CHECK-NOT line, if TySan will never produce more than one error.

https://github.com/llvm/llvm-project/pull/95387